Background:
Classified as echinoids, these spiny shells (The spines have been removed on these cleaned shells) are found in oceans throughout the world. Sea Urchins feed on algae and when unchecked can devastate underwater environments.
The sputnik urchin is so called due to its resemblance to the early Russian spacecraft. Sputnik is Russian for satellite or fellow traveler.

Sea Urchins in History:
Urchin is an old English word for hedgehog which describes the look of the creatures really well.

Sea Urchins in Geology: Sea urchins are prominent in pre-history with abundant numbers being found in the Devonian and Carboniferous periods. During the Permian sea urchins almost died out but the species again became more diverse through the Jurassic and Cretaceous.
As the species evolve relatively quickly they have become useful to geologists for dating rocks.